AScribe Newswire

LOS ANGELES, July 19 (AScribe Newswire) -- It is the world's most commonly used illicit drug, and perhaps the most controversial of all substances. Marijuana has been at the center of debate for decades, with equal numbers calling for its legalization and ban.

In his new book, "Understanding Marijuana" (Oxford University Press, 2002) Mitch Earleywine, an associate professor of psychology at the University of Southern California, attempts to sort out myths and facts about the drug. After analyzing some 500 studies, Earleywine's ultimate conclusion is mixed - marijuana is neither completely harmless nor tragically toxic.

"The common human desire is to split the world into two categories," said Earleywine, an expert on substance abuse and personality "Decisions are easier when everything is black or white. Yet the world remains in glorious color."

Earleywine looks at the history of medical and recreational marijuana use, cannabis pharmacology, health effects and treatment.

After examining studies dating from 1681 to 2001, Earleywine has arrived at a number of conclusions, including:

- Daily marijuana use alters brain function. About 10 percent of regular users develop troubles ranging from memory lapses and paranoia to an increased tolerance to the drug.

- Marijuana does not spur aggressive behavior or impede motivation.

- Marijuana is not a gateway drug and is less harmful than tobacco and alcohol. Less than 1 percent of marijuana users try heroin.

- While marijuana does help glaucoma, it is not as effective as recently developed Canasol eye drops, which do not cause any intoxication and last much longer.

- Users cannot learn new material while they are high on marijuana. Studies show an impairment in "free recall" memory and find that users are unable to separate relevant from irrelevant stimuli.

- Unlike alcohol or aspirin, marijuana has never been known to cause a lethal overdose.

- Between 200 million and 300 million people claim to have tried the drug at least once, with far fewer identifying as regular users. In the United States, fewer than 5 percent of Americans report using the drug every week.

Earleywine cautions that an incomplete reading of research can support any argument for or against marijuana. After examining the studies, he found that some researchers ignored crucial information and data in their final analyses.

For example, he said, studies slanted against marijuana legalization mention that tetrahydrocannabinol (THC), the main active chemical in marijuana, often appears in the blood of people involved in auto accidents; But the studies fail to mention that most of these people also had high blood-alcohol levels.

Similarly, studies slanted in favor of marijuana legalization cite a large study that showed no sign of memory problems in chronic marijuana smokers. However, they neglect to mention that the tests were so easy that even a young child could perform them.

"Researchers' interpretations may tell more about their own biases than they do about the data," Earleywine said. "I have tried to avoid this problem by providing appropriate detail about research so that readers can interpret results for themselves."

Earleywine said that some research concludes that marijuana prohibition may cost more than it saves. More than 500,000 people are arrested each year for offenses related to cannabis.

"Whatever the benefits of marijuana prohibition, the laws also generate costs. These include the price of law enforcement and incarceration. In addition, the taxes that a legal marijuana market could generate are also lost," Earleywine said.

The federal government spends $15.7 billion annually on drug prohibition, while state and local governments spend approximately $16 billion annually enforcing drug laws, for a total of nearly $32 billion. Approximately 43 percent (642,000) of the 1.5 million drug arrests in 1996 were for marijuana offenses. If all arrests were equally costly, America spent $13.7 billion on marijuana arrests - approximately $21,400 for each one, said the researcher.

"Some arrests undoubtedly cost more than others," Earleywine said. "Even if marijuana enforcement cost only half this amount, Americans have clearly spent billions in an attempt to eradicate this drug, and will likely continue to do so."